Measuring instrument



Oct. 24, 1944. J, A. CALDWELL 2,3

MEASURING INSTRUMENT Original Filed Dec. 15, 1938 s Sheets-Sheet 1 z FIGJ.

'INVENTOR JOHN A. CALDWELL 7 ATTORNEY v Oct. 24, 1944. J, A. CALDWELL MEASURING INSTRUMENT Original Filed Dec. 15, 1938 3 Sheets-Sheet 2 1H Hi ll UTHIHHIIII H E mw a N N E R M m in Oct. 24, 1944.

J. A. CALDWELL MEASURING INSTRUMENT 3 Sheets-Sheet 3 Original Filed Dec. 15. 1958 FIG. 4-.

mm F iNV-ENTOR JOHN A. CALDWELL ATTORNEY Patented Uct. 24, 1944 UNITED STATES PATENT OFFICE.

MEASURING INSTRUMENT Original application December 15, 1938, Serial Divided and this application September 21, 1939, Serial No. 295,846

6 Claims. (Cl. 23456) The present invention is a division of my copen'ding application Serial Number 245,928, flied December 15, 1938, now Patent No. 2,275,246 issu d March 3, 1942, and relates to high speed measuring and recording apparatus in which it is desirable to obtain an accurate record of the value of the condition being measured and to obtain a knowledge of the time that the record was made.

In instruments of this type as the record is being made, if the value of the condition remains approximately constant, the chart upon which the record is recorded may be driven at a fairly low speed and the record will still be entirely legible. Upon the occurrence of sudden and large changes in the value of the condition, however, it is desirable to have a detailed knowledge of the changes and in order to obtain them the chart must be driven at a much higher rate of speed. Inasmuch as these changes may occur at any time it is desirable if not necessary that the change in chart speed be responsive to the alteration of the condition a predetermined amount from normal.v

In the ordinary type of chart used on recording instruments the chart is provided with vertical lines to indicate the value of the condition and horizontal lines to indicate the time at which the record was made. If, however, the chart is driven at different speeds at irregular intervals the normal time lines become useless and some auxiliary means is necessary in order to indicate time on the chart.

It is an object of the invention to provide a means to mark the time of day on the chart at periodic intervals so that regardless oi the speed of the chart the correct time 01 the record will always be indicated thereon.

The various features or novelty which charac-.

terize my invention are pointed out with particularity in the claims annexed to andforming a partof this specification. For a better understanding of the invention, however;:its advantages and specific objects obtained with its use.

Fig. 4 is a sectionview taken on line 4-4 of Fig. 2; and

Fig. 5 is a section view taken on line 5-5 oi Fig. 4.

There is illustrated in Fig. 1, one form which an instrument of the present invention may take. The instrument is provided with some suitable casing that has a door I hinged at one side to the casing and provided at its other side with a combined knob and lock 2 by which the door may be opened to provide access to the mechanism in the casing. A glass window is in the door through which may be seen various of the essential parts of the mechanism which will be described in detall later.

The instrument is provided with a high speed measuring system of any desired type, and may well take the form of that shown in the application of Thomas R. Harrison, Serial Number 145,- 637, filed on May 29, 1937, now Patent 2,245,034 issued June 10, 1941. Such a. system is used to measure, for example, the temperature of a hot body such as a billet as it is being moved from a heating furnace to the rolls of a rolling mill or as it passes between the rolls. The instrument is so constructed that normally a pen i5 forming part thereof is positioned at the low or left side of the chart I. When the temperature of a billet is being measured, however, thehelically threaded shaft I2 is rotated an amount proportional to the value of the billet temperature to move a pen carriage 13 carrying the pen It to the right to a position corresponding to the value of that temperature. As the pen carriage 13 moves to the right it actuates a mechanism to speed up the chart l5 upon which the record of the temperature is being made.

By the use of a chart driving mechanism that has two speeds the chart is driven at the high speed only as long as the emergency exists, or as long as the billet is passing the measuring element. At all other times the chart is driven at a slow or normal speed. This prevents unnecessary waste of the chart inasmuch as it is not run at a high speed any longer than necessary. In the ordinary instrument in which the chart is provided with horizontal time lines such an arrangement would render them useless because of the irregular changes of chart speed. In order to overcome this necessary disadvantage I provide as my invention a device to mark on the chart the time of day at periodic intervals, so that the time any part or the record was made may be easily ascertained. When the multi-speed chart drive and time printing mechanism are used together on the same instrument a high speed legible and easily interpreted record line is produced. The normal horizontal lines may, if desired, be retained on the chart to be used for convenience in interpolating the time of the readings between the periodically printed time marks. It is preferable that the high speed drive have some definite relation to the low speed drive, such as a speed in inches per hour at low speed and the same number of inches per minute at high speed.

There is shown in Figs. 2 to 5 one form of time printing mechanism that may be used, and the drive means therefor. Referring first to Fig. 2 there is shown in dotted outline a synchronous motor I3 that has on its-drive shaft a pinion 14 which, through gearing now to be described, drives the printing mechanism. The pinion I4 meshes with and drives .a gear 15 which carries a pair of pawls 16 that are spring pressed into engagement with a ratchet 11 which is fast on shaft 18. The gear I5 is loosely journaled on the shaft I8, the arrangement being that the shaft I8 may be rotated if desired by some manual means, such as a knob in the end of the shaft, faster than it'is normally driven by motor 18.

Fastened to the shaft 18 is a pinion 1.8 that meshes with and drives a gear 88 and pinion 8|. The gear 80 drives a pinion 82, attached to one end of a shaft 83, to the other end of which is fastened a disc 84 having a slot 84A in it. Rotatable on the shaft 88 is a cam 85 that is adjustably secured to the disc 84 by means of a screw extending through the slot 84A and into the cam. The arrangement is such that the cam 85 is driven at a fairly high speed from the gear 15. The pinion 8|, driven with gear 88, meshes with and drives a gear 88, that along with a gear 81 and a cam 88, is attached to a sleeve 88 which rotates on the shaft 83. In this manner, the earns 85 and 88 are mounted side by side and rotated at different speeds, the cam 85 rotating faster than the cam 88.

A supporting plate 88 for the printing mechanism per se is pivoted at 8| to the right hand side plate 82 of the instrument. The lower edge of plate 88 is bent as shown at 88A and is also provided with a roller 83. The plate 88 is biased by gravity and a spring 8IA to hold the edge 88A close to and roller 83 in engagement with the earns 85 and 88 so that as the cut-out portions 85A and 88A of the cams 85 and 88, respectively, move under the edge and roller the plate 88 will be permitted to move clockwise to bring the time printing characters into engagement with chart I5. The roller 93 normally bears against the cams 85 and 88 so that the frictional drag on the cams will be small, but just prior to the time that printing is to occur the roller 88 passes out of engagement with the cams and the edge 88A comes into engagement therewith. The purpose of this is to give a sharp, quick action to the plate 88 that cannot be obtained when the roller 88 moves off the edge of the cam. The cams 85 and 88 are so adjusted relative to each other that periodically, say every five minutes, the leading edges of their cut-out portions will simultaneously move in a clockwise direction past edge 98A so that a printing operation may take place. Almost immediately thereafter the cam 85 rotating at hi h speed, engages roller 88 to move the plate 80 counterclockwise to lift the rint wheels out of engagement with the chart I5. During this initial rotation of the cam 85 after a printing operation has taken place the roller 83 and edge 90A will be moved by that cam to the positon shown in Figure 2. Also during this rotation of cam the cam 88 will have rotated sumciently so that the following edge of cut-out portion 88A will be beyond the edge "A to hold plate 88 in its Figure 2 position until another printing operation is to take place. The cam 85 is rotating rapidly enough so that it will lift the printing character out of engagement with the chart before the chart, if moving at a high speed, can blur the printing.

The gear 81 meshes with a gear 84, rotatable around the threaded shaft II, which gear drives the printing mechanism that is more clearly shown in Figs. 3 to 5. Meshing with and rotated at a constant speed by gear 84 is a gear 85 that is attached to a gear 88. both of the latter being rotatable around a sleeve 81 on pivot pin 8|. It is noted that plate 88 is attached to the sleeve 81 so that the sleeve 81 and plate 88 oscillate together around pin 8| to perform the printing operation. The gears 88 and 88 are of slightly different diameters and they drive gears 88 and 88, respectively, at such relative speeds that the gear 88 rotates one and one-twelfth times for each rotation of the gear 88. The gear 88 is shown as being integrally formed with a minute print wheel I88 that has twelve printing characters I8I formed on its surface. The speed of rotation of the print wheel is such that it is driven from motor 18 through the above described gear train at a rate of one and onetwelfth revolutions each five minutes. In this manner a different printing character is brought into printing position every five minutes.

The gear 88 rotates on a sleeve I82 that is attached to and rotated by the gear 88, and the sleeve revolves around a tubular journal I88 which is rigidly attached to plate 88, Rotatably supported by a web or discI84 formed on the end of sleeve I82 and extending radially therefrom is an hour print wheel I85 that is provided on its periphery with printing characters I88. This print wheel I85 is formed as an annular member and is provided with a series of openings in it through which extend pins I81 that are attached to a disc I88 mounted on shaft I88. The shaft extends through the hollow Journal I88 and is biased toward the right to maintain pins I81 in the print wheel I85 by means'of a spring H8 bearing at one end against journal I88 and at its other end against a knob III on the shaft. The pins I81 also extend into openings in an annular internal gear H2 that is mounted on the web or disc I84 beside the print wheel I85. The gear 88 drives the hour print wheel I85 at the speed of one revolution every five minutes so that every five minutes the sam character I88 is in printing position.

From the above it will be seen that the same printing character on the hour wheel will continuously return to printing position while a new character on the minute wheel will be placed in printing position at the end of each interval of five minutes. Means are provided to advance the hour wheel one-twelfth of a revolution relative to the minute wheel at the end of every twelve printin oprations, or at the end of each hour. This is accomplished in the following manner.

The disc I84 is provided with a small stud shaft H8 extending therefrom, upon which is journaled a small pinion H4 having six teeth every other one of which is shorter than those adjacent it as shown at a in Fig. 4. The interior of print wheel I88 is formed in cross-section with a step I IS in which is formed one depressed gear tooth IIS and with a step III in which are formed two raised gear teeth II8, the depression IIB being located in between the teeth II8. Normally two long teeth of the pinion III are resting on the step H5 while the intermediate short tooth is extending downwardly toward the step III. In this manner the pinion H4 is normally locked against rotation and since its teeth are at all times in mesh with those of internal gear II2, that gear and the hour print wheel attached thereto by pins I'I are prevented from rotating with respect to their driving shaft, sleeve I02.

During the operation of the device between the times the hour wheel is to be stepped forward'relative to the minute wheel, the long teeth of the pinion Ill rest on step II5. Since the hour and minute wheels are rotating at different speeds the pinion II4 will be held from rotation but .will slide on the faster rotating steps IIS and III. At the end of every twelve revolutions of the hour wheel the minute wheel will have advanced one complete turn relative thereto and during the next revolution teeth H8 and H8, formed in the steps, will move under the pinion to revolve it on shaft II3. This will, due to the meshin of pinion I and gear II2, forcethat gear along with the print wheel I05 and disc I08 ahead of disc I04 for one-twelfth ofa revolution to bring the next hour printing character I06 into printing position.

In order to supply ink to the printing wheels 3, pair of felt ink pads II9, held in metal supports I20, are loosely mounted on the sleeve 81. The ink pads are held in place by a washer I2I. As the print wheels rotate the ink pads are rotated with them to continuously keep the printing characters moist so that a good impression will be made on the chart.

In the operation of the printing mechanism the motor I8 rotates at a constant speed and drives the cams 05 and 88 past edge 90A. At the same time the motor I3 is rotating the print wheels I00 and I05. The gearing is so adjusted that-every time the low portions of the cams come under edge 00A a pair of printing characters, one on each print wheel, are in print- Ing position. Thereafter as edge 80A falls of! the cams a recording of the time is made on the chart. At intervals of five minutes new println characters will be brought into printing position and th cams will have rotated to again bring their low portions under edge 90A to repeat the operation. It will be obvious that the gearing and print wheel mechanism above described may be altered so that the time may be printed on the chart at other intervals of time rather than the five minute intervals above described.

Provisions are made for setting the print wheels so that they will print the proper time -of day regardless of their position when the gagement with internal gear II2. Knob III can now be rotated and through disc I08 and pins I01 the print wheel I05 may be rotated relative to print wheel I00 to place the proper hour character I00 in printing position over the chart.

In order to facilitate the adjustment of the print wheels each of them is provided with numbers on its surface, between the characters MI and I06, angularly displaced from the latter an amount so that when a character IM or I08 is in printing position the corresponding number will be opposite a pointer I22 located at a readily visible position on plate 90. In setting the wheels the shaft I8 is first manually rotated until the proper number on wheel I00 is opposite pointer I22 thus indicating that the proper character IOI is in printing position. Thereafter knob III is pushed to the left and rotated until the proper number on wheel. I05 is opposite pointer I22 to indicate that the proper character I06 is in printing position. If desired a mark I23 may be placed on the shoulder of gear 98 in such a position that just as the printing operation is to take place the mark I23 will be centered in an opening in the pointer. This may then serve as an indication that a printing operation is about to take place.

Switches may be located at the front of th instrument above the chart and pen mechanism to control the various motors that drive the elements of the instrument. Such switches have been shown in the upper part of Fig. 1.

From the above description it will be seen that I have provided a mechanism which, when used in a recording instrument, will produce an extremely legible and well correlated record.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims, and that in some cases certain features of my invention may sometimes be used to advantage without a corresponding use of other features.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a measuring instrument having a chart and drive means for said chart, the combination of time marking means for said chart, said marking means comprising, a rockable support, a pair of print wheels on said support and normally out of engagement with the chart, means to continuously rotate said print wheels at different rates of speed, whereby periodically different indicia will be brought into a position to print on said chart, means to continuously tend to move said support in a direction to bring said wheels into engagement with said chart, and means to keep said wheels out of engagement with said chart and operated in synchronism with said wheels to periodically release said support when the wheels are in said position to print on said chart.

2. In a measuring instrument having a chart, the combination. of means to print the time of day on, the chart comprising an hour print wheel and a minute print wheel, means to continuously drive said print wheels at different speeds and means to step said hour wheel ahead one-twelfth of a revolution each thirteen revolutions of said minute print wheel.

3. In a time printing mechanism, a Support rotatable about a first axis, a print wheel mounted on said support to rotate about a second axis displaced from said first axis, an ink pad mounted for rotation about said first axis, the periphe'ry of the ink pad being in frictional driving engagement with the periphery of the print wheel to be driven thereby as the print wheel rotates, and means to pivot said support around said first axis, the arrangement being that said ink pad is always in engagement with the print wheel.

4. In a measuring instrument having a chart, a time marking means for the chart comprising in combination a pivotally mounted support, printing means on said support adapted to be moved with said support into printing engagement with the chart, means to bias said support to printing position, a cam follower on said support, means to keep normally said support out or printing position comprising a pair 01' cams against which said cam follower bears, means to rotate said cams at diflerent speeds, the faster rotating cam having a depression with an abrupt leading edge and a gradually rising trailing edge, the slower rotating cam having a depression with abrupt leading and trailing edges, said cams beof rotatably mounted time printing wheels on said support, a constantly rotating drive means for said wheels, a gear train between said drive means and said wheels, an overrunning clutch in said gear train, manually operated means to rotate that portion of the gear train between the overrunning clutch and said wheels whereby said wheels may be rotated faster by said manually operated means than they are by said constantly rotating means, and means to rotate one 01 said wheels relative to the other, whereby both of said wheels may be rotated by said manually operated means until said other wheel is properly positioned and said one wheel may be rotated relative to said other wheel until said one wheel is properly positioned so that the setting of said wheels may be quickly changed.

6. In a measuring instrument having a chart and a means to make continuously a record on said chart, the combination of means to print the time 0! day on the chart to show when the record thereon was made including a support, an hour print wheel and a minute print wheel rotatably mounted on said support, a train 0! gears by which said print wheels are rotated, said gear train including an overrunning clutch, constantly rotating drive means to drive said clutch and thereby rotate said gear train and print wheels at one speed, manually operated means to rotate said clutch and thereby rotate said gear train and print wheels at a faster speed, and other manually operable means to rotate said hour print wheel relative to said minute print wheel whereby said print wheels may readily be set to print the correct time of day.

JOHN A. CALDWELL. 

